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dp-packet: Refactor DPDK packet initialization.

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DPDK uses dp-packet pools and manages the mbuf portion of
each packet. When a pool is created, partial initialization is
also done on the OVS portion (i.e. non-mbuf).  Since packet
memory is reused, this is not very useful for transient
fields and is also misleading.  Furthermore, some of these
transient fields are properly initialized for DPDK packets
entering OVS anyways, which is the only reasonable way to do this.
Another field, cutlen, is initialized in this manner in the pool
and intended to be reset when cutlen is applied on sending the
packet out. However, if cutlen context is set but the packet is
not sent out for some reason, then the packet header would be
corrupted in the memory pool.  It is better to just reset the
cutlen in the packets when received.  I did not detect a
degradation in performance, however, I would be willing to
have some degradation, since this is a proper way to handle
this.  In addition to initializing cutlen in received packets,
the other OVS transient fields are removed from the DPDK pool
initialization.

Acked-by: Sugesh Chandran <sugesh.chandran@intel.com>
Signed-off-by: Darrell Ball <dlu998@gmail.com>
This commit is contained in:
Darrell Ball
2017-08-24 22:09:58 -07:00
parent 441cb3ebc0
commit 11d4c7a843
3 changed files with 21 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
lib/dp-packet.c
View File

@@ -92,16 +92,18 @@ dp_packet_use_const(struct dp_packet *b, const void *data, size_t size)
dp_packet_set_size(b, size);
}
/* Initializes 'b' as an empty dp_packet that contains the 'allocated' bytes of
* memory starting at 'base'. DPDK allocated dp_packet and *data is allocated
* from one continous memory region, so in memory data start right after
* dp_packet. Therefore there is special method to free this type of
* buffer. dp_packet base, data and size are initialized by dpdk rcv() so no
* need to initialize those fields. */
/* Initializes 'b' as an empty dp_packet that contains the 'allocated' bytes.
* DPDK allocated dp_packet and *data is allocated from one continous memory
* region as part of memory pool, so in memory data start right after
* dp_packet. Therefore, there is a special method to free this type of
* buffer. Here, non-transient ovs dp-packet fields are initialized for
* packets that are part of a DPDK memory pool. */
void
dp_packet_init_dpdk(struct dp_packet *b, size_t allocated)
{
dp_packet_init__(b, allocated, DPBUF_DPDK);
dp_packet_set_allocated(b, allocated);
b->source = DPBUF_DPDK;
b->packet_type = htonl(PT_ETH);
}
/* Initializes 'b' as an empty dp_packet with an initial capacity of 'size'

10
lib/dp-packet.h
View File

@@ -800,6 +800,16 @@ dp_packet_delete_batch(struct dp_packet_batch *batch, bool may_steal)
}
}
static inline void
dp_packet_batch_init_cutlen(struct dp_packet_batch *batch)
{
struct dp_packet *packet;
DP_PACKET_BATCH_FOR_EACH (packet, batch) {
dp_packet_reset_cutlen(packet);
}
}
static inline void
dp_packet_batch_apply_cutlen(struct dp_packet_batch *batch)
{

2
lib/netdev-dpdk.c
View File

@@ -1644,6 +1644,7 @@ netdev_dpdk_vhost_rxq_recv(struct netdev_rxq *rxq,
nb_rx, dropped);
rte_spinlock_unlock(&dev->stats_lock);
dp_packet_batch_init_cutlen(batch);
batch->count = (int) nb_rx;
return 0;
}
@@ -1683,6 +1684,7 @@ netdev_dpdk_rxq_recv(struct netdev_rxq *rxq, struct dp_packet_batch *batch)
rte_spinlock_unlock(&dev->stats_lock);
}
dp_packet_batch_init_cutlen(batch);
batch->count = nb_rx;
return 0;